You might have seen their strategically self-regarding emails or watched their self-inflating egos in work meetings.
But business school researchers have identified a type of employee who manages to look busy and successful, without actually doing anything useful.
The productivity study examined 28 UK workplaces and found staff who appeared to be "highly engaged".
But on closer inspection they were found to be "self-promoters" whose lack of effort pushed down overall output.
The research, from the Ashridge at Hult International Business School, examined the engagement levels of teams of workers, across seven different employment sectors, such as health, government, transport and not-for-profits.
It found some very motivated workers - and some who were plainly disgruntled and disaffected.
But about one in five teams was a conundrum - where staff appeared to be very engaged, but where teamwork and productivity were poor.
The study found when "lifting the lid" on these groups of workers, that they were undermined by staff who were successfully "gaming the system" but not really getting anything done.
They might constantly appear in a circuit of meetings, or get involved in conversations that were to their own advantage - but apart from playing the corporate culture, it was difficult to see what they actually achieved.
In shift work, it could mean stretching out work to fit across the hours with the least effort.
These have been labelled the "pseudo-engaged" by employment researchers, as opposed to the "engaged" and "disengaged".
'Dysfunctional' but rewarded
Senior researcher Amy Armstrong said such "selfish" staff undermined teamwork and damaged productivity - and in a business sense had a negative impact.
But she said the pseudo-engaged could often be encouraged by the managerial system.
"They're rewarded for that dysfunctional behaviour," said Dr Armstrong.
They were more likely to get promotions, better pay and bonuses and to devote even more of their efforts to their own careers - to the detriment of collective productivity.
"It's quite a depressing picture," she said.
This was often because such staff were "managing upwards" by making themselves look good in front of senior managers.
Staff who spent their time promoting themselves in meetings were likely to benefit more than colleagues who were doing the work.
Such workplaces could outwardly appear to have lots of commitment and support for company goals.
But below the surface the researchers found "low levels of trust and cohesion" with "little evidence of collegiality or support for one another".
It can leave other staff feeling stretched and without any sense of "togetherness".
Dr Armstrong said in such workplaces there can appear to be "no point to teamwork" because of the individuals who seem to benefit from their self-promotion.